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authorLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 19:02:39 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-22 19:02:39 -0700
commitbbd9d6f7fbb0305c9a592bf05a32e87eb364a4ff (patch)
tree12b2bb4202b05f6ae6a43c6ce830a0472043dbe5 /Documentation
parent8e204874db000928e37199c2db82b7eb8966cc3c (diff)
parent5a9a43646cf709312d71eca71cef90ad802f28f9 (diff)
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Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6
* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs-2.6: (107 commits) vfs: use ERR_CAST for err-ptr tossing in lookup_instantiate_filp isofs: Remove global fs lock jffs2: fix IN_DELETE_SELF on overwriting rename() killing a directory fix IN_DELETE_SELF on overwriting rename() on ramfs et.al. mm/truncate.c: fix build for CONFIG_BLOCK not enabled fs:update the NOTE of the file_operations structure Remove dead code in dget_parent() AFS: Fix silly characters in a comment switch d_add_ci() to d_splice_alias() in "found negative" case as well simplify gfs2_lookup() jfs_lookup(): don't bother with . or .. get rid of useless dget_parent() in btrfs rename() and link() get rid of useless dget_parent() in fs/btrfs/ioctl.c fs: push i_mutex and filemap_write_and_wait down into ->fsync() handlers drivers: fix up various ->llseek() implementations fs: handle SEEK_HOLE/SEEK_DATA properly in all fs's that define their own llseek Ext4: handle SEEK_HOLE/SEEK_DATA generically Btrfs: implement our own ->llseek fs: add SEEK_HOLE and SEEK_DATA flags reiserfs: make reiserfs default to barrier=flush ... Fix up trivial conflicts in fs/xfs/linux-2.6/xfs_super.c due to the new shrinker callout for the inode cache, that clashed with the xfs code to start the periodic workers later.
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/Locking8
-rw-r--r--Documentation/filesystems/porting27
-rw-r--r--Documentation/filesystems/vfs.txt30
3 files changed, 53 insertions, 12 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index 57d827d6071d..ca7e25292542 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -52,7 +52,7 @@ ata *);
void (*put_link) (struct dentry *, struct nameidata *, void *);
void (*truncate) (struct inode *);
int (*permission) (struct inode *, int, unsigned int);
- int (*check_acl)(struct inode *, int, unsigned int);
+ int (*check_acl)(struct inode *, int);
int (*setattr) (struct dentry *, struct iattr *);
int (*getattr) (struct vfsmount *, struct dentry *, struct kstat *);
int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
@@ -412,7 +412,7 @@ prototypes:
int (*open) (struct inode *, struct file *);
int (*flush) (struct file *);
int (*release) (struct inode *, struct file *);
- int (*fsync) (struct file *, int datasync);
+ int (*fsync) (struct file *, loff_t start, loff_t end, int datasync);
int (*aio_fsync) (struct kiocb *, int datasync);
int (*fasync) (int, struct file *, int);
int (*lock) (struct file *, int, struct file_lock *);
@@ -438,9 +438,7 @@ prototypes:
locking rules:
All may block except for ->setlease.
- No VFS locks held on entry except for ->fsync and ->setlease.
-
-->fsync() has i_mutex on inode.
+ No VFS locks held on entry except for ->setlease.
->setlease has the file_list_lock held and must not sleep.
diff --git a/Documentation/filesystems/porting b/Documentation/filesystems/porting
index 6e29954851a2..7f8861d341ea 100644
--- a/Documentation/filesystems/porting
+++ b/Documentation/filesystems/porting
@@ -400,10 +400,31 @@ a file off.
--
[mandatory]
-
---
-[mandatory]
->get_sb() is gone. Switch to use of ->mount(). Typically it's just
a matter of switching from calling get_sb_... to mount_... and changing the
function type. If you were doing it manually, just switch from setting ->mnt_root
to some pointer to returning that pointer. On errors return ERR_PTR(...).
+
+--
+[mandatory]
+ ->permission(), generic_permission() and ->check_acl() have lost flags
+argument; instead of passing IPERM_FLAG_RCU we add MAY_NOT_BLOCK into mask.
+ generic_permission() has also lost the check_acl argument; if you want
+non-NULL to be used for that inode, put it into ->i_op->check_acl.
+
+--
+[mandatory]
+ If you implement your own ->llseek() you must handle SEEK_HOLE and
+SEEK_DATA. You can hanle this by returning -EINVAL, but it would be nicer to
+support it in some way. The generic handler assumes that the entire file is
+data and there is a virtual hole at the end of the file. So if the provided
+offset is less than i_size and SEEK_DATA is specified, return the same offset.
+If the above is true for the offset and you are given SEEK_HOLE, return the end
+of the file. If the offset is i_size or greater return -ENXIO in either case.
+
+[mandatory]
+ If you have your own ->fsync() you must make sure to call
+filemap_write_and_wait_range() so that all dirty pages are synced out properly.
+You must also keep in mind that ->fsync() is not called with i_mutex held
+anymore, so if you require i_mutex locking you must make sure to take it and
+release it yourself.
diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt
index 88b9f5519af9..eff6617c9a0f 100644
--- a/Documentation/filesystems/vfs.txt
+++ b/Documentation/filesystems/vfs.txt
@@ -229,6 +229,8 @@ struct super_operations {
ssize_t (*quota_read)(struct super_block *, int, char *, size_t, loff_t);
ssize_t (*quota_write)(struct super_block *, int, const char *, size_t, loff_t);
+ int (*nr_cached_objects)(struct super_block *);
+ void (*free_cached_objects)(struct super_block *, int);
};
All methods are called without any locks being held, unless otherwise
@@ -301,6 +303,26 @@ or bottom half).
quota_write: called by the VFS to write to filesystem quota file.
+ nr_cached_objects: called by the sb cache shrinking function for the
+ filesystem to return the number of freeable cached objects it contains.
+ Optional.
+
+ free_cache_objects: called by the sb cache shrinking function for the
+ filesystem to scan the number of objects indicated to try to free them.
+ Optional, but any filesystem implementing this method needs to also
+ implement ->nr_cached_objects for it to be called correctly.
+
+ We can't do anything with any errors that the filesystem might
+ encountered, hence the void return type. This will never be called if
+ the VM is trying to reclaim under GFP_NOFS conditions, hence this
+ method does not need to handle that situation itself.
+
+ Implementations must include conditional reschedule calls inside any
+ scanning loop that is done. This allows the VFS to determine
+ appropriate scan batch sizes without having to worry about whether
+ implementations will cause holdoff problems due to large scan batch
+ sizes.
+
Whoever sets up the inode is responsible for filling in the "i_op" field. This
is a pointer to a "struct inode_operations" which describes the methods that
can be performed on individual inodes.
@@ -333,8 +355,8 @@ struct inode_operations {
void * (*follow_link) (struct dentry *, struct nameidata *);
void (*put_link) (struct dentry *, struct nameidata *, void *);
void (*truncate) (struct inode *);
- int (*permission) (struct inode *, int, unsigned int);
- int (*check_acl)(struct inode *, int, unsigned int);
+ int (*permission) (struct inode *, int);
+ int (*check_acl)(struct inode *, int);
int (*setattr) (struct dentry *, struct iattr *);
int (*getattr) (struct vfsmount *mnt, struct dentry *, struct kstat *);
int (*setxattr) (struct dentry *, const char *,const void *,size_t,int);
@@ -423,7 +445,7 @@ otherwise noted.
permission: called by the VFS to check for access rights on a POSIX-like
filesystem.
- May be called in rcu-walk mode (flags & IPERM_FLAG_RCU). If in rcu-walk
+ May be called in rcu-walk mode (mask & MAY_NOT_BLOCK). If in rcu-walk
mode, the filesystem must check the permission without blocking or
storing to the inode.
@@ -755,7 +777,7 @@ struct file_operations {
int (*open) (struct inode *, struct file *);
int (*flush) (struct file *);
int (*release) (struct inode *, struct file *);
- int (*fsync) (struct file *, int datasync);
+ int (*fsync) (struct file *, loff_t, loff_t, int datasync);
int (*aio_fsync) (struct kiocb *, int datasync);
int (*fasync) (int, struct file *, int);
int (*lock) (struct file *, int, struct file_lock *);
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