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2011-03-31Fix common misspellingsLucas De Marchi
Fixes generated by 'codespell' and manually reviewed. Signed-off-by: Lucas De Marchi <lucas.demarchi@profusion.mobi>
2011-03-24Merge branch 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.39/core' of git://git.kernel.dk/linux-2.6-block: (65 commits) Documentation/iostats.txt: bit-size reference etc. cfq-iosched: removing unnecessary think time checking cfq-iosched: Don't clear queue stats when preempt. blk-throttle: Reset group slice when limits are changed blk-cgroup: Only give unaccounted_time under debug cfq-iosched: Don't set active queue in preempt block: fix non-atomic access to genhd inflight structures block: attempt to merge with existing requests on plug flush block: NULL dereference on error path in __blkdev_get() cfq-iosched: Don't update group weights when on service tree fs: assign sb->s_bdi to default_backing_dev_info if the bdi is going away block: Require subsystems to explicitly allocate bio_set integrity mempool jbd2: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging jbd: finish conversion from WRITE_SYNC_PLUG to WRITE_SYNC and explicit plugging fs: make fsync_buffers_list() plug mm: make generic_writepages() use plugging blk-cgroup: Add unaccounted time to timeslice_used. block: fixup plugging stubs for !CONFIG_BLOCK block: remove obsolete comments for blkdev_issue_zeroout. blktrace: Use rq->cmd_flags directly in blk_add_trace_rq. ... Fix up conflicts in fs/{aio.c,super.c}
2011-03-15exofs: deprecate the commands pending counterBoaz Harrosh
One leftover from the days of IBM's original code, is an SB counter that counts in-flight asynchronous commands. And a piece of code that waits for the counter to reach zero at unmount. I guess it might have been needed then, cause of some reference missing or something. I'm not removing it yet but am putting a warning message if ever this counter triggers at unmount. If I'll never see it triggers or reported I'll remove the counter for good. (I had this print as a debug output for a long time and never had it trigger) Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Write sbi->s_nextid as part of the Create commandBoaz Harrosh
Before when creating a new inode, we'd set the sb->s_dirt flag, and sometime later the system would write out s_nextid as part of the sb_info. Also on inode sync we would force the sb sync as well. Define the s_nextid as a new partition attribute and set it every time we create a new object. At mount we read it from it's new place. We now never set sb->s_dirt anywhere in exofs. write_super is actually never called. The call to exofs_write_super from exofs_put_super is also removed because the VFS always calls ->sync_fs before calling ->put_super twice. To stay backward-and-forward compatible we also write the old s_nextid in the super_block object at unmount, and support zero length attribute on mount. This also fixes a BUG where in layouts when group_width was not a divisor of EXOFS_SUPER_ID (0x10000) the s_nextid was not read from the device it was written to. Because of the sliding window layout trick, and because the read was always done from the 0 device but the write was done via the raid engine that might slide the device view. Now we read and write through the raid engine. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Add option to mount by osdnameBoaz Harrosh
If /dev/osd* devices are shuffled because more devices where added, and/or login order has changed. It is hard to mount the FS you want. Add an option to mount by osdname. osdname is any osd-device's osdname as specified to the mkfs.exofs command when formatting the osd-devices. The new mount format is: OPT="osdname=$UUID0,pid=$PID,_netdev" mount -t exofs -o $OPT $DEV_OSD0 $MOUNTDIR if "osdname=" is specified in options above $DEV_OSD0 is ignored and can be empty. Also while at it: Removed some old unused Opt_* enums. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Override read-ahead to align on stripe_sizebharrosh@panasas.com
* Set all inode->i_mapping->backing_dev_info to point to the per super-block sb->s_bdi. * Calculating a read_ahead that is: - preferable 2 stripes long (Future patch will add a mount option to override this) - Minimum 128K aligned up to stripe-size - Caped to maximum-IO-sizes round down to stripe_size. (Max sizes are governed by max bio-size that fits in a page times number-of-devices) CC: Marc Dionne <marc.c.dionne@gmail.com> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: simple fsync race fixNick Piggin
It is incorrect to test inode dirty bits without participating in the inode writeback protocol. Inode writeback sets I_SYNC and clears I_DIRTY_?, then writes out the particular bits, then clears I_SYNC when it is done. BTW. it may not completely write all pages out, so I_DIRTY_PAGES would get set again. This is a standard pattern used throughout the kernel's writeback caches (I_SYNC ~= I_WRITEBACK, if that makes it clearer). And so it is not possible to determine an inode's dirty status just by checking I_DIRTY bits. Especially not for the purpose of data integrity syncs. Missing the check for these bits means that fsync can complete while writeback to the inode is underway. Inode writeback functions get this right, so call into them rather than try to shortcut things by testing dirty state improperly. Signed-off-by: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Optimize read_4_writeBoaz Harrosh
Don't attempt a read passed i_size, just zero the page and be done with it. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Trivial: fix some indentation and debug printsBoaz Harrosh
I stumbled on some of these prints in log files so, might just submit the fixes. * All i_ino prints in exofs should be hex * All OSD_ERR prints should end with a "\n" Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2011-03-15exofs: Remove redundant unlikely()Tobias Klauser
IS_ERR() already implies unlikely(), so it can be omitted here. Signed-off-by: Tobias Klauser <tklauser@distanz.ch>
2011-03-10block: remove per-queue pluggingJens Axboe
Code has been converted over to the new explicit on-stack plugging, and delay users have been converted to use the new API for that. So lets kill off the old plugging along with aops->sync_page(). Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2011-03-03exofs: i_nlink races in rename()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2011-02-02Revert "exofs: Set i_mapping->backing_dev_info anyway"Boaz Harrosh
This reverts commit 115e19c53501edc11f730191f7f047736815ae3d. Apparently setting inode->bdi to one's own sb->s_bdi stops VFS from sending *read-aheads*. This problem was bisected to this commit. A revert fixes it. I'll investigate farther why is this happening for the next Kernel, but for now a revert. I'm sending to stable@kernel.org as well, since it exists also in 2.6.37. 2.6.36 is good and does not have this patch. CC: Stable Tree <stable@kernel.org> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2011-01-07fs: icache RCU free inodesNick Piggin
RCU free the struct inode. This will allow: - Subsequent store-free path walking patch. The inode must be consulted for permissions when walking, so an RCU inode reference is a must. - sb_inode_list_lock to be moved inside i_lock because sb list walkers who want to take i_lock no longer need to take sb_inode_list_lock to walk the list in the first place. This will simplify and optimize locking. - Could remove some nested trylock loops in dcache code - Could potentially simplify things a bit in VM land. Do not need to take the page lock to follow page->mapping. The downsides of this is the performance cost of using RCU. In a simple creat/unlink microbenchmark, performance drops by about 10% due to inability to reuse cache-hot slab objects. As iterations increase and RCU freeing starts kicking over, this increases to about 20%. In cases where inode lifetimes are longer (ie. many inodes may be allocated during the average life span of a single inode), a lot of this cache reuse is not applicable, so the regression caused by this patch is smaller. The cache-hot regression could largely be avoided by using SLAB_DESTROY_BY_RCU, however this adds some complexity to list walking and store-free path walking, so I prefer to implement this at a later date, if it is shown to be a win in real situations. I haven't found a regression in any non-micro benchmark so I doubt it will be a problem. Signed-off-by: Nick Piggin <npiggin@kernel.dk>
2010-10-29convert get_sb_nodev() usersAl Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25new helper: ihold()Al Viro
Clones an existing reference to inode; caller must already hold one. Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25fs: add sync_inode_metadataChristoph Hellwig
Add a new helper to write out the inode using the writeback code, that is including the correct dirty bit and list manipulation. A few of filesystems already opencode this, and a lot of others should be using it instead of using write_inode_now which also writes out the data. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-10-25exofs: Remove inode->i_count manipulation in exofs_new_inodeBoaz Harrosh
exofs_new_inode() was incrementing the inode->i_count and decrementing it in create_done(), in a bad attempt to make sure the inode will still be there when the asynchronous create_done() finally arrives. This was very stupid because iput() was not called, and if it was actually needed, it would leak the inode. However all this is not needed, because at exofs_evict_inode() we already wait for create_done() by waiting for the object_created event. Therefore remove the superfluous ref counting and just Thicken the comment at exofs_evict_inode() a bit. While at it change places that open coded wait_obj_created() to call the already available wrapper. CC: Dave Chinner <dchinner@redhat.com> CC: Christoph Hellwig <hch@lst.de> CC: Nick Piggin <npiggin@kernel.dk> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-10-25fs/exofs: typo fix of faild to failedJoe Perches
Signed-off-by: Joe Perches <joe@perches.com> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-10-18exofs: Set i_mapping->backing_dev_info anywayBoaz Harrosh
Though it has been promised that inode->i_mapping->backing_dev_info is not used and the supporting code is fine. Until the pointer will default to NULL, I'd rather it points to the correct thing regardless. At least for future infrastructure coder it is a clear indication of where are the key points that inodes are initialized. I know because it took me time to find this out. Signed-off-by: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
2010-10-18exofs: Cleaup read path in regard with read_for_writeBoaz Harrosh
Last BUG fix added a flag to the the page_collect structure to communicate with readpage_strip. This calls for a clean up removing that flag's reincarnations in the read functions parameters. Signed-off-by: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
2010-10-08exofs: Fix double page_unlock BUG in write_begin/endBoaz Harrosh
This BUG is there since the first submit of the code, but only triggered in last Kernel. It's timing related do to the asynchronous object-creation behaviour of exofs. (Which should be investigated farther) The bug is obvious hence the fixed. Signed-off-by: Boaz Harrosh <Boaz Harrosh bharrosh@panasas.com>
2010-08-11Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osdLinus Torvalds
* 'for-linus' of git://git.open-osd.org/linux-open-osd: exofs: Fix groups code when num_devices is not divisible by group_width exofs: Remove useless optimization exofs: exofs_file_fsync and exofs_file_flush correctness exofs: Remove superfluous dependency on buffer_head and writeback
2010-08-10Merge branch 'for-2.6.36' of git://git.kernel.dk/linux-2.6-blockLinus Torvalds
* 'for-2.6.36' of git://git.kernel.dk/linux-2.6-block: (149 commits) block: make sure that REQ_* types are seen even with CONFIG_BLOCK=n xen-blkfront: fix missing out label blkdev: fix blkdev_issue_zeroout return value block: update request stacking methods to support discards block: fix missing export of blk_types.h writeback: fix bad _bh spinlock nesting drbd: revert "delay probes", feature is being re-implemented differently drbd: Initialize all members of sync_conf to their defaults [Bugz 315] drbd: Disable delay probes for the upcomming release writeback: cleanup bdi_register writeback: add new tracepoints writeback: remove unnecessary init_timer call writeback: optimize periodic bdi thread wakeups writeback: prevent unnecessary bdi threads wakeups writeback: move bdi threads exiting logic to the forker thread writeback: restructure bdi forker loop a little writeback: move last_active to bdi writeback: do not remove bdi from bdi_list writeback: simplify bdi code a little writeback: do not lose wake-ups in bdi threads ... Fixed up pretty trivial conflicts in drivers/block/virtio_blk.c and drivers/scsi/scsi_error.c as per Jens.
2010-08-09convert exofs to ->evict_inode()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09exofs: New truncate sequenceBoaz Harrosh
These changes are crafted based on the similar conversion done to ext2 by Nick Piggin. * Remove the deprecated ->truncate vector. Let exofs_setattr take care of on-disk size updates. * Call truncate_pagecache on the unused pages if write_begin/end fails. * Cleanup exofs_delete_inode that did stupid inode writes and updates on an inode that will be removed. * And finally get rid of exofs_get_block. We never had any blocks it was all for calling nobh_truncate_page. nobh_truncate_page is not actually needed in exofs since the last page is complete and gone, just like all the other pages. There is no partial blocks in exofs. I've tested with this patch, and there are no apparent failures, so far. CC: Nick Piggin <npiggin@suse.de> CC: Christoph Hellwig <hch@lst.de> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-09remove inode_setattrChristoph Hellwig
Replace inode_setattr with opencoded variants of it in all callers. This moves the remaining call to vmtruncate into the filesystem methods where it can be replaced with the proper truncate sequence. In a few cases it was obvious that we would never end up calling vmtruncate so it was left out in the opencoded variant: spufs: explicitly checks for ATTR_SIZE earlier btrfs,hugetlbfs,logfs,dlmfs: explicitly clears ATTR_SIZE earlier ufs: contains an opencoded simple_seattr + truncate that sets the filesize just above In addition to that ncpfs called inode_setattr with handcrafted iattrs, which allowed to trim down the opencoded variant. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-08-07block: unify flags for struct bio and struct requestChristoph Hellwig
Remove the current bio flags and reuse the request flags for the bio, too. This allows to more easily trace the type of I/O from the filesystem down to the block driver. There were two flags in the bio that were missing in the requests: BIO_RW_UNPLUG and BIO_RW_AHEAD. Also I've renamed two request flags that had a superflous RW in them. Note that the flags are in bio.h despite having the REQ_ name - as blkdev.h includes bio.h that is the only way to go for now. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
2010-08-04exofs: Fix groups code when num_devices is not divisible by group_widthBoaz Harrosh
There is a bug when num_devices is not divisible by group_width * mirrors. We would not return to the proper device and offset when looping on to the next group. The fix makes code simpler actually. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-08-04exofs: Remove useless optimizationBoaz Harrosh
We used to compact all used devices in an IO to the beginning of the device array in an io_state. And keep a last device used so in later loops we don't iterate on all device slots. This does not prevent us from checking if slots are empty since in reads we only read from a single mirror and jump to the next mirror-set. This optimization is marginal, and needlessly complicates the code. Specially when we will later want to support raid/456 with same abstract code. So remove the distinction between "dev" and "comp". Only "dev" is used both as the device used and as the index (component) in the device array. [Note that now the io_state->dev member is redundant but I keep it because I might want to optimize by only IOing a single group, though keeping a group_width*mirrors devices in io_state, we now keep num-devices in each io_state] Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-08-04exofs: exofs_file_fsync and exofs_file_flush correctnessBoaz Harrosh
As per Christoph advise: no need to call filemap_write_and_wait(). In exofs all metadata is at the inode so just writing the inode is all is needed. ->fsync implies this must be done synchronously. But now exofs_file_fsync can not be used by exofs_file_flush. vfs_fsync() should do that job correctly. FIXME: remove the sb_sync and fix that sb_update better. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-08-04exofs: Remove superfluous dependency on buffer_head and writebackBoaz Harrosh
exofs_releasepage && exofs_invalidatepage are never called. Leave the WARN_ONs but remove any code. Remove the cleanup other stale #includes. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-05-27drop unused dentry argument to ->fsyncChristoph Hellwig
Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-24Merge branch 'for-linus' of git://git.open-osd.org/linux-open-osdLinus Torvalds
* 'for-linus' of git://git.open-osd.org/linux-open-osd: exofs: confusion between kmap() and kmap_atomic() api exofs: Add default address_space_operations
2010-05-21exofs: replace inode uid,gid,mode initialization with helper functionDmitry Monakhov
Ack-by: Boaz Harrosh <bharrosh@panasas.com> Signed-off-by: Dmitry Monakhov <dmonakhov@openvz.org> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-05-17exofs: confusion between kmap() and kmap_atomic() apiDan Carpenter
For kmap_atomic() we call kunmap_atomic() on the returned pointer. That's different from kmap() and kunmap() and so it's easy to get them backwards. Cc: Stable <stable@kernel.org> Signed-off-by: Dan Carpenter <error27@gmail.com> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-05-17exofs: Add default address_space_operationsBoaz Harrosh
All vectors of address_space_operations should be initialized by the filesystem. Add the missing parts. This is actually an optimization, by using __set_page_dirty_nobuffers. The default, in case of NULL, would be __set_page_dirty_buffers which has these extar if(s). .releasepage && .invalidatepage should both not be called because page_private() is NULL in exofs. Put a WARN_ON if they are called, to indicate the Kernel has changed in this regard, if when it does. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-04-29exofs: Fix "add bdi backing to mount session" fall outBoaz Harrosh
Commit b3d0ab7e60d1865bb6f6a79a77aaba22f2543236 ("exofs: add bdi backing to mount session") has a bug in the placement of the bdi member at struct exofs_sb_info. The layout member must be kept last. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com> Acked-by: Jens Axboe <jens.axboe@oracle.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2010-04-22exofs: add bdi backing to mount sessionJens Axboe
This ensures that dirty data gets flushed properly. Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2010-03-30include cleanup: Update gfp.h and slab.h includes to prepare for breaking ↵Tejun Heo
implicit slab.h inclusion from percpu.h percpu.h is included by sched.h and module.h and thus ends up being included when building most .c files. percpu.h includes slab.h which in turn includes gfp.h making everything defined by the two files universally available and complicating inclusion dependencies. percpu.h -> slab.h dependency is about to be removed. Prepare for this change by updating users of gfp and slab facilities include those headers directly instead of assuming availability. As this conversion needs to touch large number of source files, the following script is used as the basis of conversion. http://userweb.kernel.org/~tj/misc/slabh-sweep.py The script does the followings. * Scan files for gfp and slab usages and update includes such that only the necessary includes are there. ie. if only gfp is used, gfp.h, if slab is used, slab.h. * When the script inserts a new include, it looks at the include blocks and try to put the new include such that its order conforms to its surrounding. It's put in the include block which contains core kernel includes, in the same order that the rest are ordered - alphabetical, Christmas tree, rev-Xmas-tree or at the end if there doesn't seem to be any matching order. * If the script can't find a place to put a new include (mostly because the file doesn't have fitting include block), it prints out an error message indicating which .h file needs to be added to the file. The conversion was done in the following steps. 1. The initial automatic conversion of all .c files updated slightly over 4000 files, deleting around 700 includes and adding ~480 gfp.h and ~3000 slab.h inclusions. The script emitted errors for ~400 files. 2. Each error was manually checked. Some didn't need the inclusion, some needed manual addition while adding it to implementation .h or embedding .c file was more appropriate for others. This step added inclusions to around 150 files. 3. The script was run again and the output was compared to the edits from #2 to make sure no file was left behind. 4. Several build tests were done and a couple of problems were fixed. e.g. lib/decompress_*.c used malloc/free() wrappers around slab APIs requiring slab.h to be added manually. 5. The script was run on all .h files but without automatically editing them as sprinkling gfp.h and slab.h inclusions around .h files could easily lead to inclusion dependency hell. Most gfp.h inclusion directives were ignored as stuff from gfp.h was usually wildly available and often used in preprocessor macros. Each slab.h inclusion directive was examined and added manually as necessary. 6. percpu.h was updated not to include slab.h. 7. Build test were done on the following configurations and failures were fixed. CONFIG_GCOV_KERNEL was turned off for all tests (as my distributed build env didn't work with gcov compiles) and a few more options had to be turned off depending on archs to make things build (like ipr on powerpc/64 which failed due to missing writeq). * x86 and x86_64 UP and SMP allmodconfig and a custom test config. * powerpc and powerpc64 SMP allmodconfig * sparc and sparc64 SMP allmodconfig * ia64 SMP allmodconfig * s390 SMP allmodconfig * alpha SMP allmodconfig * um on x86_64 SMP allmodconfig 8. percpu.h modifications were reverted so that it could be applied as a separate patch and serve as bisection point. Given the fact that I had only a couple of failures from tests on step 6, I'm fairly confident about the coverage of this conversion patch. If there is a breakage, it's likely to be something in one of the arch headers which should be easily discoverable easily on most builds of the specific arch. Signed-off-by: Tejun Heo <tj@kernel.org> Guess-its-ok-by: Christoph Lameter <cl@linux-foundation.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
2010-03-05pass writeback_control to ->write_inodeChristoph Hellwig
This gives the filesystem more information about the writeback that is happening. Trond requested this for the NFS unstable write handling, and other filesystems might benefit from this too by beeing able to distinguish between the different callers in more detail. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2010-02-28exofs: groups supportBoaz Harrosh
* _calc_stripe_info() changes to accommodate for grouping calculations. Returns additional information * old _prepare_pages() becomes _prepare_one_group() which stores pages belonging to one device group. * New _prepare_for_striping iterates on all groups calling _prepare_one_group(). * Enable mounting of groups data_maps (group_width != 0) [QUESTION] what is faster A or B; A. x += stride; x = x % width + first_x; B x += stride if (x < last_x) x = first_x; Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: Prepare for groupsBoaz Harrosh
* Rename _offset_dev_unit_off() to _calc_stripe_info() and recieve a struct for the output params * In _prepare_for_striping we only need to call _calc_stripe_info() once. The other componets are easy to calculate from that. This code was inspired by what's done in truncate. * Some code shifts that make sense now but will make more sense when group support is added. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: Error recovery if object is missing from storageBoaz Harrosh
If an object is referenced by a directory but does not exist on a target, it is a very serious corruption that means: 1. Either a power failure with very slim chance of it happening. Because the directory update is always submitted much after object creation, but if a directory is written to one device and the object creation to another it might theoretically happen. 2. It only ever happened to me while developing with BUGs causing file corruption. Crashes could also cause it but they are more like case 1. In any way the object does not exist, so data is surely lost. If there is a mix-up in the obj-id or data-map, then lost objects can be salvaged by off-line fsck. The only recoverable information is the directory name. By letting it appear as a regular empty file, with date==0 (1970 Jan 1st) ownership to root, we enable recovery of the only useful information. And also enable deletion or over-write. I can see how this can hurt. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: convert io_state to use pages array instead of bio at inputBoaz Harrosh
* inode.c operations are full-pages based, and not actually true scatter-gather * Lets us use more pages at once upto 512 (from 249) in 64 bit * Brings us much much closer to be able to use exofs's io_state engine from objlayout driver. (Once I decide where to put the common code) After RAID0 patch the outer (input) bio was never used as a bio, but was simply a page carrier into the raid engine. Even in the simple mirror/single-dev arrangement pages info was copied into a second bio. It is now easer to just pass a pages array into the io_state and prepare bio(s) once. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: RAID0 supportBoaz Harrosh
We now support striping over mirror devices. Including variable sized stripe_unit. Some limits: * stripe_unit must be a multiple of PAGE_SIZE * stripe_unit * stripe_count is maximum upto 32-bit (4Gb) Tested RAID0 over mirrors, RAID0 only, mirrors only. All check. Design notes: * I'm not using a vectored raid-engine mechanism yet. Following the pnfs-objects-layout data-map structure, "Mirror" is just a private case of "group_width" == 1, and RAID0 is a private case of "Mirrors" == 1. The performance lose of the general case over the particular special case optimization is totally negligible, also considering the extra code size. * In general I added a prepare_stripes() stage that divides the to-be-io pages to the participating devices, the previous exofs_ios_write/read, now becomes _write/read_mirrors and a new write/read upper layer loops on all devices calling _write/read_mirrors. Effectively the prepare_stripes stage is the all secret. Also truncate need fixing to accommodate for striping. * In a RAID0 arrangement, in a regular usage scenario, if all inode layouts will start at the same device, the small files fill up the first device and the later devices stay empty, the farther the device the emptier it is. To fix that, each inode will start at a different stripe_unit, according to it's obj_id modulus number-of-stripe-units. And will then span all stripe-units in the same incrementing order wrapping back to the beginning of the device table. We call it a stripe-units moving window. Special consideration was taken to keep all devices in a mirror arrangement identical. So a broken osd-device could just be cloned from one of the mirrors and no FS scrubbing is needed. (We do that by rotating stripe-unit at a time and not a single device at a time.) TODO: We no longer verify object_length == inode->i_size in exofs_iget. (since i_size is stripped on multiple objects now). I should introduce a multiple-device attribute reading, and use it in exofs_iget. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: Define on-disk per-inode optional layout attributeBoaz Harrosh
* Layouts describe the way a file is spread on multiple devices. The layout information is stored in the objects attribute introduced in this patch. * There can be multiple generating function for the layout. Currently defined: - No attribute present - use below moving-window on global device table, all devices. (This is the only one currently used in exofs) - an obj_id generated moving window - the obj_id is a randomizing factor in the otherwise global map layout. - An explicit layout stored, including a data_map and a device index list. - More might be defined in future ... * There are two attributes defined of the same structure: A-data-files-layout - This layout is used by data-files. If present at a directory, all files of that directory will be created with this layout. A-meta-data-layout - This layout is used by a directory and other meta-data information. Also inherited at creation of subdirectories. * At creation time inodes are created with the layout specified above. A usermode utility may change the creation layout on a give directory or file. Which in the case of directories, will also apply to newly created files/subdirectories, children of that directory. In the simple unaltered case of a newly created exofs, no layout attributes are present, and all layouts adhere to the layout specified at the device-table. * In case of a future file system loaded in an old exofs-driver. At iget(), the generating_function is inspected and if not supported will return an IO error to the application and the inode will not be loaded. So not to damage any data. Note: After this patch we do not yet support any type of layout only the RAID0 patch that enables striping at the super-block level will add support for RAID0 layouts above. This way we are past and future compatible and fully bisectable. * Access to the device table is done by an accessor since it will change according to above information. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: unindent exofs_sbi_readBoaz Harrosh
The original idea was that a mirror read can be sub-divided to multiple devices. But this has very little gain and only at very large IOes so it's not going to be implemented soon. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: Move layout related members to a layout structureBoaz Harrosh
* Abstract away those members in exofs_sb_info that are related/needed by a layout into a new exofs_layout structure. Embed it in exofs_sb_info. * At exofs_io_state receive/keep a pointer to an exofs_layout. No need for an exofs_sb_info pointer, all we need is at exofs_layout. * Change any usage of above exofs_sb_info members to their new name. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
2010-02-28exofs: Recover in the case of read-passed-end-of-fileBoaz Harrosh
In check_io, implement the case of reading passed end of file, by clearing the pages and recover with no error. In a raid arrangement this can become a legitimate situation in case of holes in the file. Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>