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2010-03-01GFS2: Metadata address space clean upSteven Whitehouse
Since the start of GFS2, an "extra" inode has been used to store the metadata belonging to each inode. The only reason for using this inode was to have an extra address space, the other fields were unused. This means that the memory usage was rather inefficient. The reason for keeping each inode's metadata in a separate address space is that when glocks are requested on remote nodes, we need to be able to efficiently locate the data and metadata which relating to that glock (inode) in order to sync or sync and invalidate it (depending on the remotely requested lock mode). This patch adds a new type of glock, which has in addition to its normal fields, has an address space. This applies to all inode and rgrp glocks (but to no other glock types which remain as before). As a result, we no longer need to have the second inode. This results in three major improvements: 1. A saving of approx 25% of memory used in caching inodes 2. A removal of the circular dependency between inodes and glocks 3. No confusion between "normal" and "metadata" inodes in super.c Although the first of these is the more immediately apparent, the second is just as important as it now enables a number of clean ups at umount time. Those will be the subject of future patches. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-12-17kill I_LOCKChristoph Hellwig
After I_SYNC was split from I_LOCK the leftover is always used together with I_NEW and thus superflous. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-16sanitize xattr handler prototypesChristoph Hellwig
Add a flags argument to struct xattr_handler and pass it to all xattr handler methods. This allows using the same methods for multiple handlers, e.g. for the ACL methods which perform exactly the same action for the access and default ACLs, just using a different underlying attribute. With a little more groundwork it'll also allow sharing the methods for the regular user/trusted/secure handlers in extN, ocfs2 and jffs2 like it's already done for xfs in this patch. Also change the inode argument to the handlers to a dentry to allow using the handlers mechnism for filesystems that require it later, e.g. cifs. [with GFS2 bits updated by Steven Whitehouse <swhiteho@redhat.com>] Signed-off-by: Christoph Hellwig <hch@lst.de> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Joel Becker <joel.becker@oracle.com> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2009-12-03GFS2: Tag all metadata with jidSteven Whitehouse
There are two spare field in the header common to all GFS2 metadata. One is just the right size to fit a journal id in it, and this patch updates the journal code so that each time a metadata block is modified, we tag it with the journal id of the node which is performing the modification. The reason for this is that it should make it much easier to debug issues which arise if we can tell which node was the last to modify a particular metadata block. Since the field is updated before the block is written into the journal, each journal should only contain metadata which is tagged with its own journal id. The one exception to this is the journal header block, which might have a different node's id in it, if that journal was recovered by another node in the cluster. Thus each journal will contain a record of which nodes recovered it, via the journal header. The other field in the metadata header could potentially be used to hold information about what kind of operation was performed, but for the time being we just zero it on each transaction so that if we use it for that in future, we'll know that the information (where it exists) is reliable. I did consider using the other field to hold the journal sequence number, however since in GFS2's journaling we write the modified data into the journal and not the original data, this gives no information as to what action caused the modification, so I think we can probably come up with a better use for those 64 bits in the future. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-12-03GFS2: Clean up ACLsSteven Whitehouse
To prepare for support for caching of ACLs, this cleans up the GFS2 ACL support by pushing the xattr code back into xattr.c and changing the acl_get function into one which only returns ACLs so that we can drop the caching function into it shortly. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-08-27GFS2: Remove no_formal_ino generating codeSteven Whitehouse
The inum structure used throughout GFS2 has two fields. One no_addr is the disk block number of the inode in question and is used everywhere as the inode number. The other, no_formal_ino, is used only as the generation number for NFS. Historically the no_formal_ino field was set using a complicated system of one global and one per-node file containing inode numbers in order to ensure that each no_formal_ino was unique. Also this code made no provision for what would happen when eventually the (64 bit) numbers ran out. Now I know that is pretty unlikely to happen given the large space of numbers, but it is possible nevertheless. The only guarantee required for no_formal_ino is that, for any single inode, the same number doesn't get reused too quickly. We already have a generation number which is kept in the inode and initialised from a counter in the resource group (almost no overhead, since we have to touch the resource group anyway in order to allocate an inode in the first place). Aside from ensuring that we never use the value 0 in the no_formal_ino field, we can use that counter directly. As a result of that change, we lose about 200 lines of code and also gain about 10 creates/sec on the postmark benchmark (on my test machine). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-08-26GFS2: Rename eattr.[ch] as xattr.[ch]Steven Whitehouse
Use the more conventional name for the extended attribute support code. Update all the places which care. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-08-26GFS2: Clean up of extended attribute supportSteven Whitehouse
This has been on my list for some time. We need to change the way in which we handle extended attributes to allow faster file creation times (by reducing the number of transactions required) and the extended attribute code is the main obstacle to this. In addition to that, the VFS provides a way to demultiplex the xattr calls which we ought to be using, rather than rolling our own. This patch changes the GFS2 code to use that VFS feature and as a result the code shrinks by a couple of hundred lines or so, and becomes easier to read. I'm planning on doing further clean up work in this area, but this patch is a good start. The cleaned up code also uses the more usual "xattr" shorthand, I plan to eliminate the use of "eattr" eventually and in the mean time it serves as a flag as to which bits of the code have been updated. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-08-17GFS2: Improve error handling in inode allocationSteven Whitehouse
A little while back, block allocation was given some improved error handling which meant that -EIO was returned in the case of there being a problem in the resource group data. In addition a message is printed explaning what went wrong and how to fix it. This extends that error handling so that it also covers inode allocation too. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-22GFS2: Move gfs2_unlink_ok into ops_inode.cSteven Whitehouse
Another function which is only called from one ops_inode.c so we move it and make it static. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-22GFS2: Move gfs2_readlinki into ops_inode.cSteven Whitehouse
Move gfs2_readlinki into ops_inode.c and make it static Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-22GFS2: Move gfs2_rmdiri into ops_inode.cSteven Whitehouse
Move gfs2_rmdiri() into ops_inode.c and make it static. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-05-22GFS2: Clean up some file namesSteven Whitehouse
This patch renames the ops_*.c files which have no counterpart without the ops_ prefix in order to shorten the name and make it more readable. In addition, ops_address.h (which was very small) is moved into inode.h and inode.h is cleaned up by adding extern where required. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-04-15GFS2: cleanup file_operations messChristoph Hellwig
Remove the weird pointer to file_operations mess and replace it with straight-forward defining of the lockinginstance names to the _nolock variants. Signed-off-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-03-24GFS2: Merge lock_dlm module into GFS2Steven Whitehouse
This is the big patch that I've been working on for some time now. There are many reasons for wanting to make this change such as: o Reducing overhead by eliminating duplicated fields between structures o Simplifcation of the code (reduces the code size by a fair bit) o The locking interface is now the DLM interface itself as proposed some time ago. o Fewer lookups of glocks when processing replies from the DLM o Fewer memory allocations/deallocations for each glock o Scope to do further optimisations in the future (but this patch is more than big enough for now!) Please note that (a) this patch relates to the lock_dlm module and not the DLM itself, that is still a separate module; and (b) that we retain the ability to build GFS2 as a standalone single node filesystem with out requiring the DLM. This patch needs a lot of testing, hence my keeping it I restarted my -git tree after the last merge window. That way, this has the maximum exposure before its merged. This is (modulo a few minor bug fixes) the same patch that I've been posting on and off the the last three months and its passed a number of different tests so far. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Kill two daemons with one patchSteven Whitehouse
This patch removes the two daemons, gfs2_scand and gfs2_glockd and replaces them with a shrinker which is called from the VM. The net result is that GFS2 responds better when there is memory pressure, since it shrinks the glock cache at the same rate as the VFS shrinks the dcache and icache. There are no longer any time based criteria for shrinking glocks, they are kept until such time as the VM asks for more memory and then we demote just as many glocks as required. There are potential future changes to this code, including the possibility of sorting the glocks which are to be written back into inode number order, to get a better I/O ordering. It would be very useful to have an elevator based workqueue implementation for this, as that would automatically deal with the read I/O cases at the same time. This patch is my answer to Andrew Morton's remark, made during the initial review of GFS2, asking why GFS2 needs so many kernel threads, the answer being that it doesn't :-) This patch is a net loss of about 200 lines of code. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Banish struct gfs2_dinode_hostSteven Whitehouse
The final field in gfs2_dinode_host was the i_flags field. Thats renamed to i_diskflags in order to avoid confusion with the existing inode flags, and moved into the inode proper at a suitable location to avoid creating a "hole". At that point struct gfs2_dinode_host is no longer needed and as promised (quite some time ago!) it can now be removed completely. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Move i_size from gfs2_dinode_host and rename it to i_disksizeSteven Whitehouse
This patch moved the i_size field from the gfs2_dinode_host and following the ext3 convention renames it i_disksize. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Move di_eattr into "proper" inodeSteven Whitehouse
This moves the di_eattr field out of gfs2_inode_host and into the inode proper. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Move "entries" into "proper" inodeSteven Whitehouse
This moves the directory entry count into the proper inode. Potentially we could get this to share the space used by something else in the future, but this is one more step on the way to removing the gfs2_dinode_host structure. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Move generation number into "proper" part of inodeSteven Whitehouse
This moves the generation number from the gfs2_dinode_host into the gfs2_inode structure. Eventually the plan is to get rid of the gfs2_dinode_host structure completely. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2009-01-05GFS2: Rationalise header filesSteven Whitehouse
Move the contents of some headers which contained very little into more sensible places, and remove the original header files. This should make it easier to find things. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-11-14CRED: Wrap task credential accesses in the GFS2 filesystemDavid Howells
Wrap access to task credentials so that they can be separated more easily from the task_struct during the introduction of COW creds. Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id(). Change some task->e?[ug]id to task_e?[ug]id(). In some places it makes more sense to use RCU directly rather than a convenient wrapper; these will be addressed by later patches. Signed-off-by: David Howells <dhowells@redhat.com> Reviewed-by: James Morris <jmorris@namei.org> Acked-by: Serge Hallyn <serue@us.ibm.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Cc: cluster-devel@redhat.com Signed-off-by: James Morris <jmorris@namei.org>
2008-09-18GFS2: high time to take some time over atimeSteven Whitehouse
Until now, we've used the same scheme as GFS1 for atime. This has failed since atime is a per vfsmnt flag, not a per fs flag and as such the "noatime" flag was not getting passed down to the filesystems. This patch removes all the "special casing" around atime updates and we simply use the VFS's atime code. The net result is that GFS2 will now support all the same atime related mount options of any other filesystem on a per-vfsmnt basis. We do lose the "lazy atime" updates, but we gain "relatime". We could add lazy atime to the VFS at a later date, if there is a requirement for that variant still - I suspect relatime will be enough. Also we lose about 100 lines of code after this patch has been applied, and I have a suspicion that it will speed things up a bit, even when atime is "on". So it seems like a nice clean up as well. From a user perspective, everything stays the same except the loss of the per-fs atime quantum tweekable (ought to be per-vfsmnt at the very least, and to be honest I don't think anybody ever used it) and that a number of options which were ignored before now work correctly. Please let me know if you've got any comments. I'm pushing this out early so that you can all see what my plans are. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-09-05GFS2: Use an IS_ERR test rather than a NULL testJulien Brunel
In case of error, the function gfs2_inode_lookup returns an ERR pointer, but never returns a NULL pointer. So a NULL test that necessarily comes after an IS_ERR test should be deleted, and a NULL test that may come after a call to this function should be strengthened by an IS_ERR test. The semantic match that finds this problem is as follows: (http://www.emn.fr/x-info/coccinelle/) // <smpl> @match_bad_null_test@ expression x, E; statement S1,S2; @@ x = gfs2_inode_lookup(...) ... when != x = E * if (x != NULL) S1 else S2 // </smpl> Signed-off-by: Julien Brunel <brunel@diku.dk> Signed-off-by: Julia Lawall <julia@diku.dk> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-08-27GFS2: Fix & clean up GFS2 renameSteven Whitehouse
This patch fixes a locking issue in the rename code by ensuring that we hold the per sb rename lock over both directory and "other" renames which involve different parent directories. At the same time, this moved the (only called from one place) function gfs2_ok_to_move into the file that its called from, so we can mark it static. This should make a code a bit easier to follow. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Peter Staubach <staubach@redhat.com>
2008-07-26[PATCH] don't pass nameidata to gfs2_lookupi()Al Viro
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2008-07-10[GFS2] Remove support for unused and pointless flagSteven Whitehouse
The ability to mark files for direct i/o access when opened normally is both unused and pointless, so this patch removes support for that feature. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-07-03[GFS2] don't call permission()Miklos Szeredi
GFS2 calls permission() to verify permissions after locks on the files have been taken. For this it's sufficient to call gfs2_permission() instead. This results in the following changes: - IS_RDONLY() check is not performed - IS_IMMUTABLE() check is not performed - devcgroup_inode_permission() is not called - security_inode_permission() is not called IS_RDONLY() should be unnecessary anyway, as the per-mount read-only flag should provide protection against read-only remounts during operations. do_gfs2_set_flags() has been fixed to perform mnt_want_write()/mnt_drop_write() to protect against remounting read-only. IS_IMMUTABLE has been added to gfs2_permission() Repeating the security checks seems to be pointless, as they don't normally change, and if they do, it's independent of the filesystem state. Signed-off-by: Miklos Szeredi <mszeredi@suse.cz> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-05-12[GFS2] filesystem consistency error from do_stripBob Peterson
This patch fixes a GFS2 filesystem consistency error reported from function do_strip. The problem was caused by a timing window that allowed two vfs inodes to be created in memory that point to the same file. The problem is fixed by making the vfs's iget_test, iget_set mechanism check and set a new bit in the in-core gfs2_inode structure while the vfs inode spin_lock is held. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-04-10[GFS2] fix GFP_KERNEL misusesJosef Bacik
There are several places where GFP_KERNEL allocations happen under a glock, which will result in hangs if we're under memory pressure and go to re-enter the fs in order to flush stuff out. This patch changes the culprits to GFS_NOFS to keep this problem from happening. Thank you, Signed-off-by: Josef Bacik <jbacik@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] possible null pointer dereference fixupCyrill Gorcunov
gfs2_alloc_get may fail so we have to check it to prevent NULL pointer dereference. Signed-off-by: Cyrill Gorcunov <gorcunov@gamil.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] re-support special inodeDenis Cheng
a previous commit removed call to init_special_inode from inode lookuping, this cause problems as: # mknod /mnt/gfs2/dev/null c 1 3 # cat /mnt/gfs2/dev/null cat: /mnt/gfs2/dev/null: Invalid argument without special inode, GFS2 cannot support char device file, block device file, fifo pipe, and socket file, lose many important features as a common file system. this one line patch re add special inode support. Signed-off-by: Denis Cheng <crquan@gmail.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] remove gfs2_dev_iopsDenis Cheng
struct inode_operations gfs2_dev_iops is always the same as gfs2_file_iops, since Jan 2006, when GFS2 merged into mainstream kernel. So one of them could be removed. Signed-off-by: Denis Cheng <crquan@gmail.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Fix a page lock / glock deadlockSteven Whitehouse
We've previously been using a "try lock" in readpage on the basis that it would prevent deadlocks due to the inverted lock ordering (our normal lock ordering is glock first and then page lock). Unfortunately tests have shown that this isn't enough. If the glock has a demote request queued such that run_queue() in the glock code tries to do a demote when its called under readpage then it will try and write out all the dirty pages which requires locking them. This then deadlocks with the page locked by readpage. The solution is to always require two calls into readpage. The first unlocks the page, gets the glock and returns AOP_TRUNCATED_PAGE, the second does the actual readpage and unlocks the glock & page as required. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Eliminate (almost) duplicate field from gfs2_inodeSteven Whitehouse
The blocks counter is almost a duplicate of the i_blocks field in the VFS inode. The only difference is that i_blocks can be only 32bits long for 32bit arch without large single file support. Since GFS2 doesn't handle the non-large single file case (for 32 bit anyway) this adds a new config dependency on 64BIT || LSF. This has always been the case, however we've never explicitly said so before. Even if we do add support for the non-LSF case, we will still not require this field to be duplicated since we will not be able to access oversized files anyway. So the net result of all this is that we shave 8 bytes from a gfs2_inode and get our config deps correct. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Reduce inode size by merging fieldsSteven Whitehouse
There were three fields being used to keep track of the location of the most recently allocated block for each inode. These have been merged into a single field in order to better keep the data and metadata for an inode close on disk, and also to reduce the space required for storage. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Shrink & rename di_depthSteven Whitehouse
This patch forms a pair with the previous patch which shrunk di_height. Like that patch di_depth is renamed i_depth and moved into struct gfs2_inode directly. Also the field goes from 16 bits to 8 bits since it is also limited to a max value which is rather small (17 in this case). In addition we also now validate the field against this maximum value when its read in. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Fix debug inode printingBob Peterson
I noticed that the latest change to i_height got rid of the value from the inode dump. This patch adds it back. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-03-31[GFS2] Streamline indirect pointer tree height calculationSteven Whitehouse
This patch improves the calculation of the tree height in order to reduce the number of operations which are carried out on each call to gfs2_block_map. In the common case, we now make a single comparison, rather than calculating the required tree height from scratch each time. Also in the case that the tree does need some extra height, we start from the current height rather from zero when we work out what the new height ought to be. In addition the di_height field is moved into the inode proper and reduced in size to a u8 since the value must be between 0 and GFS2_MAX_META_HEIGHT (10). Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-02-07iget: use iget_failed() in GFS2David Howells
Use iget_failed() in GFS2 to kill a failed inode. Signed-off-by: David Howells <dhowells@redhat.com> Cc: Steven Whitehouse <swhiteho@redhat.com> Acked-by: Christoph Hellwig <hch@lst.de> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2008-01-25[GFS2] Lockup on errorBob Peterson
I spotted this bug while I was digging around. Looks like it could cause a lockup in some rare error condition. Signed-off-by: Bob Peterson <rpeterso@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Reduce inode size by moving i_alloc out of lineSteven Whitehouse
It is possible to reduce the size of GFS2 inodes by taking the i_alloc structure out of the gfs2_inode. This patch allocates the i_alloc structure whenever its needed, and frees it afterward. This decreases the amount of low memory we use at the expense of requiring a memory allocation for each page or partial page that we write. A quick test with postmark shows that the overhead is not measurable and I also note that OCFS2 use the same approach. In the future I'd like to solve the problem by shrinking down the size of the members of the i_alloc structure, but for now, this reduces the immediate problem of using too much low-memory on x86 and doesn't add too much overhead. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Remove lock methods for lock_nolock protocolWendy Cheng
GFS2 supports two modes of locking - lock_nolock for single node filesystem and lock_dlm for cluster mode locking. The gfs2 lock methods are removed from file operation table for lock_nolock protocol. This would allow VFS to handle posix lock and flock logics just like other in-tree filesystems without duplication. Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Don't add glocks to the journalSteven Whitehouse
The only reason for adding glocks to the journal was to keep track of which locks required a log flush prior to release. We add a flag to the glock to allow this check to be made in a simpler way. This reduces the size of a glock (by 12 bytes on i386, 24 on x86_64) and means that we can avoid extra work during the journal flush. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Introduce gfs2_set_aops()Steven Whitehouse
Just like ext3 we now have three sets of address space operations to cover the cases of writeback, ordered and journalled data writes. This means that the individual operations can now become less complicated as we are able to remove some of the tests for file data mode from the code. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Remove useless i_cache from inodesSteven Whitehouse
The i_cache was designed to keep references to the indirect blocks used during block mapping so that they didn't have to be looked up continually. The idea failed because there are too many places where the i_cache needs to be freed, and this has in the past been the cause of many bugs. In addition there was no performance benefit being gained since the disk blocks in question were cached anyway. So this patch removes it in order to simplify the code to prepare for other changes which would otherwise have had to add further support for this feature. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2008-01-25[GFS2] Clean up internal read functionSteven Whitehouse
As requested by Christoph, this patch cleans up GFS2's internal read function so that it no longer uses the do_generic_mapping_read function. This function is obsolete and GFS2 is the last user of it. As a side effect the internal read code gets smaller and easier to read and gfs2_readpage is split into two. One function has the locking and the other function has the rest of the logic. Signed-off-by: Steven Whitehouse <swhiteho@redhat.com> Cc: Christoph Hellwig <hch@infradead.org>
2007-10-10[GFS2] Alternate gfs2_iget to avoid looking up inodes being freedBenjamin Marzinski
There is a possible deadlock between two processes on the same node, where one process is deleting an inode, and another process is looking for allocated but unused inodes to delete in order to create more space. process A does an iput() on inode X, and it's i_count drops to 0. This causes iput_final() to be called, which puts an inode into state I_FREEING at generic_delete_inode(). There no point between when iput_final() is called, and when I_FREEING is set where GFS2 could acquire any glocks. Once I_FREEING is set, no other process on that node can successfully look up that inode until the delete finishes. process B locks the the resource group for the same inode in get_local_rgrp(), which is called by gfs2_inplace_reserve_i() process A tries to lock the resource group for the inode in gfs2_dinode_dealloc(), but it's already locked by process B process B waits in find_inode for the inode to have the I_FREEING state cleared. Deadlock. This patch solves the problem by adding an alternative to gfs2_iget(), gfs2_iget_skip(), that simply skips any inodes that are in the I_FREEING state.o The alternate test function is just like the original one, except that it fails if the inode is being freed, and sets a skipped flag. The alternate set function is just like the original, except that it fails if the skipped flag is set. Only try_rgrp_unlink() calls gfs2_iget_skip() instead of gfs2_iget(). Signed-off-by: Benjamin E. Marzinski <bmarzins@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>
2007-10-10[GFS2] fix inode meta data corruptionWendy Cheng
Fix a nasty inode meta data corruption issue by keeping the buffer head in icache array. This buffer needs to stay in memory until journal flush occurs Otherwise, gfs2_meta_inode_buffer could do a disk read before the inode hits disk. It ends up with meta data corruptions. The buffer will be released as part of the existing journal flush logic. Signed-off-by: S. Wendy Cheng <wcheng@redhat.com> Signed-off-by: Steven Whitehouse <swhiteho@redhat.com>