diff options
Diffstat (limited to 'Documentation/filesystems')
| -rw-r--r-- | Documentation/filesystems/Locking | 35 | ||||
| -rw-r--r-- | Documentation/filesystems/proc.txt | 7 | ||||
| -rw-r--r-- | Documentation/filesystems/vfs.txt | 49 |
3 files changed, 60 insertions, 31 deletions
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking index 9858f337529c..fe7afe225381 100644 --- a/Documentation/filesystems/Locking +++ b/Documentation/filesystems/Locking @@ -11,10 +11,8 @@ be able to use diff(1). prototypes: int (*d_revalidate)(struct dentry *, unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); - int (*d_hash)(const struct dentry *, const struct inode *, - struct qstr *); - int (*d_compare)(const struct dentry *, const struct inode *, - const struct dentry *, const struct inode *, + int (*d_hash)(const struct dentry *, struct qstr *); + int (*d_compare)(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); int (*d_delete)(struct dentry *); void (*d_release)(struct dentry *); @@ -66,6 +64,7 @@ prototypes: int (*atomic_open)(struct inode *, struct dentry *, struct file *, unsigned open_flag, umode_t create_mode, int *opened); + int (*tmpfile) (struct inode *, struct dentry *, umode_t); locking rules: all may block @@ -93,6 +92,7 @@ removexattr: yes fiemap: no update_time: no atomic_open: yes +tmpfile: no Additionally, ->rmdir(), ->unlink() and ->rename() have ->i_mutex on victim. @@ -344,25 +344,38 @@ prototypes: locking rules: - file_lock_lock may block + inode->i_lock may block fl_copy_lock: yes no fl_release_private: maybe no ----------------------- lock_manager_operations --------------------------- prototypes: int (*lm_compare_owner)(struct file_lock *, struct file_lock *); + unsigned long (*lm_owner_key)(struct file_lock *); void (*lm_notify)(struct file_lock *); /* unblock callback */ int (*lm_grant)(struct file_lock *, struct file_lock *, int); void (*lm_break)(struct file_lock *); /* break_lease callback */ int (*lm_change)(struct file_lock **, int); locking rules: - file_lock_lock may block -lm_compare_owner: yes no -lm_notify: yes no -lm_grant: no no -lm_break: yes no -lm_change yes no + + inode->i_lock blocked_lock_lock may block +lm_compare_owner: yes[1] maybe no +lm_owner_key yes[1] yes no +lm_notify: yes yes no +lm_grant: no no no +lm_break: yes no no +lm_change yes no no + +[1]: ->lm_compare_owner and ->lm_owner_key are generally called with +*an* inode->i_lock held. It may not be the i_lock of the inode +associated with either file_lock argument! This is the case with deadlock +detection, since the code has to chase down the owners of locks that may +be entirely unrelated to the one on which the lock is being acquired. +For deadlock detection however, the blocked_lock_lock is also held. The +fact that these locks are held ensures that the file_locks do not +disappear out from under you while doing the comparison or generating an +owner key. --------------------------- buffer_head ----------------------------------- prototypes: diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt index fd8d0d594fc7..fcc22c982a25 100644 --- a/Documentation/filesystems/proc.txt +++ b/Documentation/filesystems/proc.txt @@ -473,7 +473,8 @@ This file is only present if the CONFIG_MMU kernel configuration option is enabled. The /proc/PID/clear_refs is used to reset the PG_Referenced and ACCESSED/YOUNG -bits on both physical and virtual pages associated with a process. +bits on both physical and virtual pages associated with a process, and the +soft-dirty bit on pte (see Documentation/vm/soft-dirty.txt for details). To clear the bits for all the pages associated with the process > echo 1 > /proc/PID/clear_refs @@ -482,6 +483,10 @@ To clear the bits for the anonymous pages associated with the process To clear the bits for the file mapped pages associated with the process > echo 3 > /proc/PID/clear_refs + +To clear the soft-dirty bit + > echo 4 > /proc/PID/clear_refs + Any other value written to /proc/PID/clear_refs will have no effect. The /proc/pid/pagemap gives the PFN, which can be used to find the pageflags diff --git a/Documentation/filesystems/vfs.txt b/Documentation/filesystems/vfs.txt index e6bd1ffd821e..f93a88250a44 100644 --- a/Documentation/filesystems/vfs.txt +++ b/Documentation/filesystems/vfs.txt @@ -360,6 +360,8 @@ struct inode_operations { int (*removexattr) (struct dentry *, const char *); void (*update_time)(struct inode *, struct timespec *, int); int (*atomic_open)(struct inode *, struct dentry *, + int (*tmpfile) (struct inode *, struct dentry *, umode_t); +} ____cacheline_aligned; struct file *, unsigned open_flag, umode_t create_mode, int *opened); }; @@ -472,6 +474,9 @@ otherwise noted. component is negative or needs lookup. Cached positive dentries are still handled by f_op->open(). + tmpfile: called in the end of O_TMPFILE open(). Optional, equivalent to + atomically creating, opening and unlinking a file in given directory. + The Address Space Object ======================== @@ -554,7 +559,6 @@ your filesystem. The following members are defined: struct address_space_operations { int (*writepage)(struct page *page, struct writeback_control *wbc); int (*readpage)(struct file *, struct page *); - int (*sync_page)(struct page *); int (*writepages)(struct address_space *, struct writeback_control *); int (*set_page_dirty)(struct page *page); int (*readpages)(struct file *filp, struct address_space *mapping, @@ -576,6 +580,9 @@ struct address_space_operations { /* migrate the contents of a page to the specified target */ int (*migratepage) (struct page *, struct page *); int (*launder_page) (struct page *); + int (*is_partially_uptodate) (struct page *, read_descriptor_t *, + unsigned long); + void (*is_dirty_writeback) (struct page *, bool *, bool *); int (*error_remove_page) (struct mapping *mapping, struct page *page); int (*swap_activate)(struct file *); int (*swap_deactivate)(struct file *); @@ -607,13 +614,6 @@ struct address_space_operations { In this case, the page will be relocated, relocked and if that all succeeds, ->readpage will be called again. - sync_page: called by the VM to notify the backing store to perform all - queued I/O operations for a page. I/O operations for other pages - associated with this address_space object may also be performed. - - This function is optional and is called only for pages with - PG_Writeback set while waiting for the writeback to complete. - writepages: called by the VM to write out pages associated with the address_space object. If wbc->sync_mode is WBC_SYNC_ALL, then the writeback_control will specify a range of pages that must be @@ -742,6 +742,20 @@ struct address_space_operations { prevent redirtying the page, it is kept locked during the whole operation. + is_partially_uptodate: Called by the VM when reading a file through the + pagecache when the underlying blocksize != pagesize. If the required + block is up to date then the read can complete without needing the IO + to bring the whole page up to date. + + is_dirty_writeback: Called by the VM when attempting to reclaim a page. + The VM uses dirty and writeback information to determine if it needs + to stall to allow flushers a chance to complete some IO. Ordinarily + it can use PageDirty and PageWriteback but some filesystems have + more complex state (unstable pages in NFS prevent reclaim) or + do not set those flags due to locking problems (jbd). This callback + allows a filesystem to indicate to the VM if a page should be + treated as dirty or writeback for the purposes of stalling. + error_remove_page: normally set to generic_error_remove_page if truncation is ok for this address space. Used for memory failure handling. Setting this implies you deal with pages going away under you, @@ -901,10 +915,8 @@ defined: struct dentry_operations { int (*d_revalidate)(struct dentry *, unsigned int); int (*d_weak_revalidate)(struct dentry *, unsigned int); - int (*d_hash)(const struct dentry *, const struct inode *, - struct qstr *); - int (*d_compare)(const struct dentry *, const struct inode *, - const struct dentry *, const struct inode *, + int (*d_hash)(const struct dentry *, struct qstr *); + int (*d_compare)(const struct dentry *, const struct dentry *, unsigned int, const char *, const struct qstr *); int (*d_delete)(const struct dentry *); void (*d_release)(struct dentry *); @@ -949,25 +961,24 @@ struct dentry_operations { d_hash: called when the VFS adds a dentry to the hash table. The first dentry passed to d_hash is the parent directory that the name is - to be hashed into. The inode is the dentry's inode. + to be hashed into. Same locking and synchronisation rules as d_compare regarding what is safe to dereference etc. d_compare: called to compare a dentry name with a given name. The first dentry is the parent of the dentry to be compared, the second is - the parent's inode, then the dentry and inode (may be NULL) of the - child dentry. len and name string are properties of the dentry to be - compared. qstr is the name to compare it with. + the child dentry. len and name string are properties of the dentry + to be compared. qstr is the name to compare it with. Must be constant and idempotent, and should not take locks if - possible, and should not or store into the dentry or inodes. - Should not dereference pointers outside the dentry or inodes without + possible, and should not or store into the dentry. + Should not dereference pointers outside the dentry without lots of care (eg. d_parent, d_inode, d_name should not be used). However, our vfsmount is pinned, and RCU held, so the dentries and inodes won't disappear, neither will our sb or filesystem module. - ->i_sb and ->d_sb may be used. + ->d_sb may be used. It is a tricky calling convention because it needs to be called under "rcu-walk", ie. without any locks or references on things. |