diff options
Diffstat (limited to 'fs/attr.c')
| -rw-r--r-- | fs/attr.c | 95 |
1 files changed, 72 insertions, 23 deletions
diff --git a/fs/attr.c b/fs/attr.c index 960a310581eb..b9ec6b47bab2 100644 --- a/fs/attr.c +++ b/fs/attr.c @@ -17,8 +17,6 @@ #include <linux/filelock.h> #include <linux/security.h> -#include "internal.h" - /** * setattr_should_drop_sgid - determine whether the setgid bit needs to be * removed @@ -232,7 +230,7 @@ EXPORT_SYMBOL(setattr_prepare); * @inode: the inode to be truncated * @offset: the new size to assign to the inode * - * inode_newsize_ok must be called with i_mutex held. + * inode_newsize_ok must be called with i_rwsem held exclusively. * * inode_newsize_ok will check filesystem limits and ulimits to check that the * new inode size is within limits. inode_newsize_ok will also send SIGXFSZ @@ -274,12 +272,45 @@ out_big: EXPORT_SYMBOL(inode_newsize_ok); /** + * setattr_copy_mgtime - update timestamps for mgtime inodes + * @inode: inode timestamps to be updated + * @attr: attrs for the update + * + * With multigrain timestamps, take more care to prevent races when + * updating the ctime. Always update the ctime to the very latest using + * the standard mechanism, and use that to populate the atime and mtime + * appropriately (unless those are being set to specific values). + */ +static void setattr_copy_mgtime(struct inode *inode, const struct iattr *attr) +{ + unsigned int ia_valid = attr->ia_valid; + struct timespec64 now; + + if (ia_valid & ATTR_CTIME_SET) + now = inode_set_ctime_deleg(inode, attr->ia_ctime); + else if (ia_valid & ATTR_CTIME) + now = inode_set_ctime_current(inode); + else + now = current_time(inode); + + if (ia_valid & ATTR_ATIME_SET) + inode_set_atime_to_ts(inode, attr->ia_atime); + else if (ia_valid & ATTR_ATIME) + inode_set_atime_to_ts(inode, now); + + if (ia_valid & ATTR_MTIME_SET) + inode_set_mtime_to_ts(inode, attr->ia_mtime); + else if (ia_valid & ATTR_MTIME) + inode_set_mtime_to_ts(inode, now); +} + +/** * setattr_copy - copy simple metadata updates into the generic inode * @idmap: idmap of the mount the inode was found from * @inode: the inode to be updated * @attr: the new attributes * - * setattr_copy must be called with i_mutex held. + * setattr_copy must be called with i_rwsem held exclusively. * * setattr_copy updates the inode's metadata with that specified * in attr on idmapped mounts. Necessary permission checks to determine @@ -305,12 +336,6 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, i_uid_update(idmap, attr, inode); i_gid_update(idmap, attr, inode); - if (ia_valid & ATTR_ATIME) - inode_set_atime_to_ts(inode, attr->ia_atime); - if (ia_valid & ATTR_MTIME) - inode_set_mtime_to_ts(inode, attr->ia_mtime); - if (ia_valid & ATTR_CTIME) - inode_set_ctime_to_ts(inode, attr->ia_ctime); if (ia_valid & ATTR_MODE) { umode_t mode = attr->ia_mode; if (!in_group_or_capable(idmap, inode, @@ -318,6 +343,19 @@ void setattr_copy(struct mnt_idmap *idmap, struct inode *inode, mode &= ~S_ISGID; inode->i_mode = mode; } + + if (is_mgtime(inode)) + return setattr_copy_mgtime(inode, attr); + + if (ia_valid & ATTR_ATIME) + inode_set_atime_to_ts(inode, attr->ia_atime); + if (ia_valid & ATTR_MTIME) + inode_set_mtime_to_ts(inode, attr->ia_mtime); + + if (ia_valid & ATTR_CTIME_SET) + inode_set_ctime_deleg(inode, attr->ia_ctime); + else if (ia_valid & ATTR_CTIME) + inode_set_ctime_to_ts(inode, attr->ia_ctime); } EXPORT_SYMBOL(setattr_copy); @@ -356,13 +394,13 @@ EXPORT_SYMBOL(may_setattr); * @attr: new attributes * @delegated_inode: returns inode, if the inode is delegated * - * The caller must hold the i_mutex on the affected object. + * The caller must hold the i_rwsem exclusively on the affected object. * * If notify_change discovers a delegation in need of breaking, * it will return -EWOULDBLOCK and return a reference to the inode in * delegated_inode. The caller should then break the delegation and * retry. Because breaking a delegation may take a long time, the - * caller should drop the i_mutex before doing so. + * caller should drop the i_rwsem before doing so. * * Alternatively, a caller may pass NULL for delegated_inode. This may * be appropriate for callers that expect the underlying filesystem not @@ -377,7 +415,7 @@ EXPORT_SYMBOL(may_setattr); * performed on the raw inode simply pass @nop_mnt_idmap. */ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, - struct iattr *attr, struct inode **delegated_inode) + struct iattr *attr, struct delegated_inode *delegated_inode) { struct inode *inode = dentry->d_inode; umode_t mode = inode->i_mode; @@ -409,22 +447,25 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, if (S_ISLNK(inode->i_mode)) return -EOPNOTSUPP; - /* Flag setting protected by i_mutex */ + /* Flag setting protected by i_rwsem */ if (is_sxid(attr->ia_mode)) inode->i_flags &= ~S_NOSEC; } now = current_time(inode); - attr->ia_ctime = now; - if (!(ia_valid & ATTR_ATIME_SET)) - attr->ia_atime = now; - else + if (ia_valid & ATTR_ATIME_SET) attr->ia_atime = timestamp_truncate(attr->ia_atime, inode); - if (!(ia_valid & ATTR_MTIME_SET)) - attr->ia_mtime = now; else + attr->ia_atime = now; + if (ia_valid & ATTR_CTIME_SET) + attr->ia_ctime = timestamp_truncate(attr->ia_ctime, inode); + else + attr->ia_ctime = now; + if (ia_valid & ATTR_MTIME_SET) attr->ia_mtime = timestamp_truncate(attr->ia_mtime, inode); + else + attr->ia_mtime = now; if (ia_valid & ATTR_KILL_PRIV) { error = security_inode_need_killpriv(dentry); @@ -489,9 +530,17 @@ int notify_change(struct mnt_idmap *idmap, struct dentry *dentry, error = security_inode_setattr(idmap, dentry, attr); if (error) return error; - error = try_break_deleg(inode, delegated_inode); - if (error) - return error; + + /* + * If ATTR_DELEG is set, then these attributes are being set on + * behalf of the holder of a write delegation. We want to avoid + * breaking the delegation in this case. + */ + if (!(ia_valid & ATTR_DELEG)) { + error = try_break_deleg(inode, delegated_inode); + if (error) + return error; + } if (inode->i_op->setattr) error = inode->i_op->setattr(idmap, dentry, attr); |